1. Field of the Invention
The present invention relates to a scanning probe microscope and probe contact sensing method thereof.
2. Description of Related Art
Conventionally, a scanning probe microscope for measuring an uneven (concave-convex) shape of a sample surface by continuously scanning a probe on the sample surface while maintaining the interaction between the probe formed at the tip of the cantilever and the sample (e.g., amplitude of the cantilever or bending of the cantilever) constant is known (see Patent Document 1). However, in the scanning probe microscope described in Patent Document 1, because the probe and the sample are always in contact, there is a possibility that wear of the probe or damage of the sample occurs.
In contrast, in Patent Documents 2 and 3, an intermittent measurement method for measuring the uneven shape of the sample surface by bringing the probe into contact with the sample surface only on a plurality of predetermined measurement points and by intermittently scanning the sample surface has been proposed. In this method, when a force (bending) applied to the cantilever becomes a certain value or more, it is determined that the probe and the sample surface are in contact, and then the height of the probe when the probe is in contact with the sample is measured. Thus, compared to Patent Document 1, the intermittent measurement method requires a minimum of contact by bringing the probe into contact with the sample surface only on the measurement points, thereby reducing wear of the probe or damage of the sample.